airplane

Not that we don’t love Star Trek, but the writers could never decide if ion propulsion was super high tech (Spock’s Brain) or something they used every day (The Menagerie). Regardless, ion propulsion is real and we have it today on more than one spacecraft. However, MIT recently demonstrated an ion-powered airplane. How exciting! An airplane with no moving parts that runs on electricity. Air travel will change forever, right? According to [Real Engineering], ion-propelled (full-sized) aircraft run into problems with the laws of physics. You can see the video explaining that, below.

To understand why, you need to know two things: how ion drive works and how the engines differ when using them in an atmosphere. Let’s start with a space-based ion engine, a topic we’ve covered before. Atoms are turned into ions which are accelerated electrically. So the ion engine is just using electricity to create thrust exhaust instead of burning rocket fuel.

Owning and flying your own small airplane offers a nearly unmatched level of freedom and autonomy. Traveling “as the crow flies” without having to deal with traffic on the ground immediately shrinks your world, and makes possible all sorts of trips and adventures. Unfortunately the crippling downsides of plane ownership (storage and maintenance costs, knowledge that you might die in a fiery crash, etc), keeps most of us planted squarely on terra firma.

But not [ITman496]. His dream of owning an ultralight has recently come true, and he’s decided to share his experience with the world. He’s got a long way to go before he slips the surly bonds of Earth, but there’s no better place to start than the beginning. In a recent blog post he documents the process of getting his new toy home, and details some of the work he plans on doing to get it airworthy.

The plane in question is a Mini-MAX that [ITman496] has determined is not only older than he is, but has never flown. It was built by a retired aircraft mechanic who unfortunately had problems with his heart towards the end of assembly. He wisely decided that he should find a safer way to spend his free time than performing solo flights in an experimental aircraft, so he put the plane up for sale.

After a considerable adventure transporting the plane back home, [ITman496] found it was stored in such good condition that the engine started right up. But that doesn’t mean it’s ready for takeoff by any stretch of the imagination. For his own safety, he’s planning on tearing down the entire plane to make sure everything is in good shape and assembled correctly; so at least he’ll only have himself to blame if anything happens when he’s in the air.

One the plane’s structure is sound, he’ll move on to some much needed engine modifications including a way to adjust the air-fuel mixture from inside the cockpit, improvements to the cooling system, and installation of a exhaust system that’s actually intended for the two-stroke engine he has. When that’s done, [ITman496] is going to move onto the real fun stuff: creating his own “glass cockpit”.

For Hackaday readers who don’t spend their time playing make believe in flight simulators, a “glass cockpit” is a general term for using digital displays rather than analog gauges in a vehicle. [ITman496] has already bought two daylight-readable 10.1″ IPS displays which he plans on driving over HDMI with the Raspberry Pi. No word on what his software setup and sensor array will look like, but we’re eager to hear more as the project progresses.

We’ve always had a fascination with things that fly. Sure, drones are the latest incarnation of that, but there have been RC planes, kites, and all sorts of flying toys and gizmos even before manned flight was possible. Maybe the first model flying machine you had was a paper airplane. There’s some debate, but it appears the Chinese and Japanese made paper airplanes 2,000 years ago. Now there’s a database of paper airplane designs, some familiar and some very cool-looking ones we just might have to try.

If you folded the usual planes in school, you’ll find those here. But you’ll also find exotic designs like the Sea Glider and the UFO. The database lets you select from planes that work better for distance, flight time, acrobatics, or decoration. You can also select the construction difficulty and if you need to make cuts in the paper or not. There are 40 designs in all at the moment. There are step-by-step instructions, printable folding instructions, and even YouTube videos showing how to build the planes.

The good news: all you need to complete the repair you’re working on is one small part. The bad news: it’s only available in a larger, expensive assembly. The worst news: shipping time is forever. We’ve all been there, and it’s a hard pill to swallow for the DIYer. Seems like a good use case for 3D-printing.

Now imagine you’re a US Marine, and instead of fixing a dishwasher or TV remote, you’ve got a $123 million F-35 fighter in the shop. The part you need is a small plastic bumper for the landing gear door, but it’s only available as part of the whole door assembly, which costs $70,000 taxpayer dollars. And lead time to get it shipped from the States is measured in weeks. Can you even entertain the notion of 3D-printing a replacement? It turns out you can, and it looks like there will be more additive manufacturing to come in Corps repair depots around the world.

Details of the printed part are not forthcoming for obvious reasons, but the part was modeled in Blender and printed in PETG on what appears to be a consumer-grade printer. The part was installed after a quick approval for airworthiness, and the grounded fighter was back in service within days. It’s encouraging that this is not a one-off; other parts have been approved for flight use by the Marines, and a whole catalog of printable parts for ground vehicles is available too. This is the reality that the 3D printing fiction of Lost in Space builds upon.

And who knows? Maybe there are field-printable parts in the disposable drones the Corps is using for standoff resupply missions.

“Surely sharpening a knife can’t be that hard” one might think, as they destroy the edge on their pocket knife by flailing it wildly against a whetstone of indeterminate grain. In reality, knife sharpening is as nuanced a practice as virtually any other field, and getting a quality finish is much harder than it seems. It also gets increasingly complex with different blades, as [Turbo Conquering Mega Eagle] shows with is customized knife sharpening jig.

The hardest part in any blade sharpening is getting the proper bevel angle. A heavy angle is good for heavy-duty tools like axes, but for fine work like shaving a more sharp angle is required. Usually, a table-mounted jig is required but due to production constraints, a handheld one was used. It’s made with push rods and a cam follower from an airplane engine (parts are plentiful since this particular engine breaks all the time) and can impart very specific bevel angles on blades. For example, machetes have a heavy angle near the handle but a finer point towards the tip, and this tool helps streamline sharpening many knives quickly.

If you want to try your hand at another project that’s not as straightforward as it might seem, you might want to build a knife from scratch before you make an attempt at a sharpening tool. It’s just as nuanced a process, but with a little practice can be done with only a few tools.

The first airplane he built was documented on YouTube over a month and a half. It was an all-electric biplane, built from insulation foam covered in fiberglass, and powered by a pair of ludicrously oversized motors usually meant for large-scale RC aircraft. This was built under Part 103 regulations — an ultralight — which means there were in effect no regulations. Anyone could climb inside one of these without a license and fly it. The plane flew, but there were a few problems. It was too fast, and the battery life wasn’t really what [Peter] wanted.

Now [Peter] is onto his next adventure. Compared to the previous plane, this has a more simplified, traditional construction. It’s a high wing monoplane with an aluminum frame. There are two motors again, although he’s still in the process of finding lower kV motors. This plane should also fly slower, longer, something you really want in an ultralight.

As far as tools required for this build, it’s surprising how few are needed to put the plane together. Of course, there are a few excessively large pop rivet guns and there will be some extra special aviation-grade bolts, but the majority of this plane will be made out of standard aluminum, insulation foam, a bit of wood, and some fiberglass. Watching [Peter] churn out high-end fabrication with these simple parts is so satisfying. If you have a drill press with a cross slide vise, you too can build a plane in your basement.

This is shaping up to be a truly fantastic build. [Peter] has already proven that yes, he can indeed build an airplane in his basement. This time, though, he’s going to have a plane that will stay in the air for more than just a few minutes.

Mini indoor drones have become an incredibly popular gift in the last few years since they’re both cool and inexpensive. For a while they’re great fun to fly around, until the inevitable collision with a wall, piece of furniture, or family member. Often not the most structurally sound of products, a slightly damaged quad can easily be confined to a cupboard for the rest of its life. But [Peter Sripol] has an idea for re-using the electronics from a mangled quad by building his own RC controlled paper aeroplane.

[Peter] uses the two rear motors from a mini quadcopter to provide the thrust for the aeroplane. The key is to remove the motors from the frame and mount them at 90 degrees to their original orientation so that they’re now facing forwards. This allows the drone’s gyro to remain facing upwards in its usual orientation, and keep the plane pointing forwards.

The reason this works is down to how drones yaw: because half of the motors spin the opposite direction to the other half, yaw is induced by increasing the speed of all motors spinning in one direction, mismatching the aerodynamic torques and rotating the drone. In the case of the mini quadcopter, each of the two rear motors spin in different directions. Therefore, when the paper plane begins to yaw off-centre, the flight controller increases power to the appropriate motor.

Mounting the flight controller and motors to the paper plane can either be achieved using a 3D-printed mount [Peter] created, or small piece of foam. Shown here is the foam design that mounts the propellers at wing level but the 3D printed version has then under the fuselage and flies a bit better.